Despite the high rates of cigarette smoking among individuals with panic attacks and panic disorder, there is very little research on the association between smoking and panic-relevant processes among youth. Indeed, there is no research that has integrated smoking with the well-established panic-relevant risk factor of anxiety sensitivity (AS) in a laboratory paradigm among youth. This relative degree of neglect is unfortunate, as adolescence is a "high-risk" developmental period during which both daily smoking and panic attacks typically first occur. Accordingly, the present proposal aims to fill this gap in the empirical literature by examining whether AS moderates the relation between smoking history and fearful-responding to a voluntary hyperventilation challenge among adolescents. The proposed study is a multimethod laboratory evaluation of emotional responding to a hyperventilation challenge. Participants will be 180 psychologically healthy adolescents, evenly divided across the various stages of smoking uptake (i.e., Non-smokers, Tried Smoking, Experimenters, Regular Smokers, and Daily Smokers). The study involves the administration of a structured clinical interview, verification of tobacco use via expired CO analyses, self-report assessments, and a hyperventilation challenge procedure. It is hypothesized that persons high in AS who are at more advanced stages of smoking uptake, relative to all other variable combinations, will evidence the highest levels of panic-relevant responding to, and slowest recovery from, the hyperventilation challenge. This research is relevant to NIH objectives because a more comprehensive understanding of the relationship between cigarette smoking and panic vulnerability will provide critical information on clinically- relevant individual differences among adolescent smokers that relate to an increased susceptibility for panic disorder development and the maintenance of smoking behavior This project is has public health significance because it focuses on two inter-related malleable risk factors for psychopathology. As such, it will inform clinical intervention efforts for both panic and smoking processes among youth. [unreadable] [unreadable] [unreadable]